The CAS Registry Mumber 80948-54-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,9,4 and 8 respectively; the second part has 2 digits, 5 and 4 respectively. Calculate Digit Verification of CAS Registry Number 80948-54: (7*8)+(6*0)+(5*9)+(4*4)+(3*8)+(2*5)+(1*4)=155 155 % 10 = 5 So 80948-54-5 is a valid CAS Registry Number.